For the past year we attempted to characterize various facets of cognitive failure in schizophrenia. In particular we have: 1. Examined working memory function using a variety of tests of so called central executive and visual and verbal and slave systems through delayed response paradigms. 2. Examining semantic memory in order to ascertain if disorganization might have effects on the ability of schizophrenic patients to communicate. We are trying to characterize differences between semantic verbal and fluency and phonological verbal fluency we are using various priming techniques to determine if there is overactivation semantic associative networks in schizophrenia that covary with "thought disorder." 3. Attempted to test the theory of delusion on hallucinatory behavior in schizophrenia that premises disconnection between a "center" that initiates action and a second "center" that monitors action. We have used delayed auditory feedback to assess this theory. 4. Examined the effects of neuroleptics on cognition schizophrenia by assessing patients' performance on neuropsychological test while they received clozapine, haloperidol or placebo. 5. Invested neuropsychological, specificity by assessing cognitive in twins discordant for bipolar illness, patients with frontal lobe epilepsy, and in patients with traumatic brain injury. 6. Assessed remote memory in schizophrenia in by testing auto biographical knowledge, information about famous people and semantic information. 7. Measured the effects of amphetamine on cognition in normal subjects and its effects while interacting with different cognitive tasks on cerebral blood flow by means of PET 015.